Role of Pentoxifylline and Celecoxib in Parkinsonism

Parkinson's disease (PD) is a chronic neurodegenerative disease clinically characterized by bradykinesia, hypokinesia, rigidity, resting tremor, and postural instability. These motor manifestations are attributed to the degeneration and selective loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc), leading to a dopamine (DA) deficiency in the striatum. The environmental factors are the most common risk factor for Parkinson's disease, while hereditary determinants have minor role for disease. Furthermore, the clinical diagnosis of PD rests on the identification of characteristics related to dopamine deficiency. However, nondopaminergic and nonmotor symptoms, including cognitive dysfunction and depression, which is one of the most common and persistent symptoms, are sometimes present at an earlier disease stage and, almost inevitably, emerge with the disease progression. Neuroinflammation is considered one of the most important factors contributing critically to pathophysiology of PD . Recently, high mobility group box-1 (HMGB1) protein has been encoded as a potential inflammatory biomarker in PD. HMGB1 mediates immune response mostly through endothelial cells and macrophage activation via targeting two vital cell receptors; Toll-like receptor 4 (TLR4) and advanced glycation end products (RAGE). HMGB1 leads to a sequential cascade of inflammatory response through enhanced release of tumor necrosis factor-alpha (TNF-α) and interleukins (ILs), prominently IL-1β and IL-6. HMGB1 mediated also up-regulation of nuclear factor kappa-β (NF-κB) with subsequent flared pro-inflammatory storm.